1. Field of the Invention
This invention relates to a conductive thin film sheet, a shield harness and a method of manufacturing the same.
2. Description of the Related Art
A motor car that is a moving body includes a wire harness arranged to supply power from a power source such a battery to electronic appliances such as various lamps and various motors mounted in the motor car, and feed a control signal to these appliances from a control device. The wire harness is composed of a plurality of electric wires.
For example, a shield wire has been used as the electric wire in order to prevent noise from invading its core from the outside. The shield wire includes a shielding potion of braid having conductivity. This shielding portion prevents noise from invading the core.
In recent years, it has been demanded that the above wire harness is manufactured at a low cost.
A proposal therefor is to wind a conductive film sheet having a thin film conductive layer around the outer periphery of electric wires not including the shielding portion. Such a configuration contributes to implementation of low cost and prevention of noise invasion. Meanwhile, in such a configuration also, in order to take out the noise, the conductive layer must be provided with a grounding wire or terminal.
This can be realized in such a manner that a hole is made in the thin film sheet, the end of the grounding wire is passed through the hole and the grounding wire is fixed to the conductive thin film sheet using a washer, bolt, nut, etc. In this case, the conductive thin film sheet must be made thin so that it can be wound around the outer periphery of the electric wires. The conductive layer must be necessarily thin.
Further, equipment of the grounding wire, which requires the washer, bolt, nut, etc., increases the number of components, thus leading to an increase in cost.
In addition, when the bolt and nut are tightened severely, the conductive layer may be broken so that the grounding wire cannot surely connected to the conductive layer. Inversely, when they are tightened loosely, the grounding wire may be disconnected from the conductive layer so that the grounding wire cannot surely connected to the conductive layer. This make it difficult to dissipate noise which tends to invade the core of the electric wire to the outside.
The above proposal will be explained in more detail referring to the drawings.
A shield harness 101 as shown in FIG. 18 is configured so that electric wires 103 with no shielding portion are bunched, and a conductive thin film sheet 102 is wound around the outer periphery of the electric wires 103.
The conductive thin film sheet 102, as seen from FIGS. 19 and 20, is composed of an insulating layer 107, a conductive layer 104 stacked thereon and a double-faced tape 116 with adhesive faces on both sides. The insulating layer 107 is composed of a first insulating layer 105 superposed on the conductive layer 104 and a second insulating layer 106 superposed on the first insulating layer 105. A pair of double-faced tapes 116 are pasted on the surface of the conductive layer 104 at both ends 102a and 102b in the widthwise direction of the conductive thin film sheet 102.
With the one both-sided tape 116 pasted on the outer periphery of the electric wires 103, the conductive thin film sheet 116 is sequentially wound around the outer periphery of the electric wires 103 from the one end 102 with the one both-sided tape 116 pasted thereon toward the other end 102b with the other both-sided tape 116 pasted thereon. Thereafter, the above other both-sided tape 116 is pasted on the conductive thin film sheet 102. Thus, the conductive thin film sheet 102 will be wound around the outer periphery of the electric wires 103. In this configuration, the shield harness 101 realizes implementation of low cost and prevention of noise invasion.
However, the structure of the shield harness 101 as shown in FIG. 18 has the following defect. Namely, in this structure, since the both-sided tapes 116 are pasted on the conductive layer 104, when the conductive thin film sheet 102 is wound around the outer periphery of the electric wires 103, a gap 120 occurs between both ends 102a and 102b where the conductive thin film sheets overlap each other in the neighborhood of the both-sided tapes 116.
Therefore, when the shield harness 101 is wired in the motor vehicle, the conductive thin film sheet 102 may develop wrinkles due to the gap 120. Then, in the neighborhood of the gap 120 and winkles, it is difficult to make sufficient electric shield.
Further, owing to vibration while the vehicle runs, the conductive thin film sheet 102 suffers from repeated flexion in the neighborhood of the gap 120 or wrinkle, the conductive layer 104 may be broken. In such a case, it becomes further difficult to make sufficient electric shield.
Accordingly, a first object of this invention is to provide a conductive thin film sheet equipped with a conductive which can surely dissipate noise which tends to invade an electric wire when it is wound around the wire, and be manufactured at low cost, and a method of manufacturing the same.
A second object of this invention is to provide a conductive thin film sheet which can surely dissipate noise which tends to invade a wire when it is wound around the wire and be made at low cost.
A third object of this invention is to provide a shield harness using the conductive thin film sheet.
In accordance with the first aspect of this invention, there is provided a conductor-equipped conductive thin film sheet comprising:
a conductive thin film sheet including a conductive layer and an insulating layer stacked on thereon; and
a conductive metallic piece bonded onto the conducive layer.
In this configuration, since the metallic piece is bonded to the conductive layer, an increase in the number of components can be prevented. Further, since the metallic piece is bonded to the conductive layer, when the conductive layer is wound around an electric wire, the noise which tends to invade the electric wire can be dissipated outwardly through the conductive layer and metallic layer.
In a preferred embodiment, the conductive thin film sheet is wound around an outer periphery of a plurality of electric wires; and
the metallic piece is shaped like a belt and extended in a longitudinal direction circumferentially of of the plurality of electric wires when the conductive thin film sheet is wound around the outer periphery of the plurality of electric wires.
By plastically deforming the metallic piece like a ring, the conductive thin film sheet can be easily wound around the outer periphery of the plurality of electric wires. The conductive thin film sheet thus wound is supported by the metallic piece plastically deformed like the ring.
In a preferred embodiment, the metallic pieces are located at both ends of the conductive thin film sheet, respectively which are spaced apart from each other in the longitudinal direction of the plurality of electric wires when the conductive thin film sheet is wound around the outer periphery of the plurality of electric wires.
Therefore, the metallic piece, when previously deformed plastically like a ring, can be easily fixed to the auxiliary machines in such a manner that tubes are passed inside the metallic pieces. Further, by tightening the metallic piece using a metallic band from outside, the metallic pieces can be surely fixed to the tubes.
In a preferred embodiment, the conductive thin film sheet is wound around the outer periphery of the plurality of electric wires in such a fashion that the conductive layer is located outside and the insulating layer is located outside. This prevents the conductive layer from being exposed and prevents the metallic piece or conductive layer from being short-circuited with another electric wire or electric appliance.
In a preferred embodiment, the metallic piece is superposed on the insulating layer and also partially bonded to the conductive layer.
In this embodiment, as compared with the case where the metallic piece is directly bonded to the conductive layer breakage of the conductive layer can be prevented effectively.
In accordance with this invention, there is also provided a method of manufacturing a conductor-equipped conductive thin film, comprising the step of:
subjecting the insulating layer and the metallic piece superposed on each other to ultrasonic welding so that the conductive layer of the conductive thin film sheet and the metallic piece are bonded to each other.
This method makes it unnecessary to remove a part of the insulating layer when the metallic piece is attached to the conductive thin film sheet. Since the conductive layer and the metallic piece are bonded to each other by ultrasonic welding, when the conductive thin film sheet is wound around the plurality of electric wires, the noise which tends to invade them can be surely dissipated.
In accordance with the second aspect of this invention, there is provided a conductive thin film sheet wound around an electric wire for preventing noise from invading the electric wire, comprising:
an insulating layer;
a conductive adhesive formed on the one principal surface of the insulating layer and at the one end of the insulating layer in a widthwise direction;
a conductive layer stacked on the one principal surface of the insulating layer;
wherein it is wound around the outer periphery of electric wire with the one end covering the other end from outside and the adhesive pasted on the other principal surface of the insulating layer.
In this configuration, since both adhesive and conductive layer are attached to the one surface of the insulating layer, when the conductive sheet is wound around the electric wire, in the vicinity of the adhesive, a gap is difficult to occur at the portion where the conductive sheets overlap each other.
In a preferred embodiment, the conductive layer is extended from an edge of the adhesive on the side of other end in the widthwise direction to the other end of the insulating layer.
Therefore, the gap is difficult to occur between the adhesive and the conductive layer in the widthwise direction. When the conductive sheet is wound around the electric wire, the gap is more difficult to occur.
In a preferred embodiment, the conductive layer has a thickness equal to that of the adhesive. Therefore, the gap is more difficult to occur in the vicinity of the adhesive.
In accordance with the second aspect of this invention, there is also provided a shield harness comprising:
a plurality of electric wires arranged in parallel; and
a conductive thin film sheet wound around the outer periphery of the plurality of electric wires to prevent noise from invading them,
wherein the conductive thin film sheet includes
an insulating layer;
a conductive adhesive formed on the one principal surface of the insulating layer and at the one end of the insulating layer in a widthwise direction;
a conductive layer stacked on the one principal surface of the insulating layer, wherein it is wound around the electric wire with the one end covering the other end from outside and the adhesive pasted on the other surface of the insulating layer.
In this configuration, since both adhesive and conductive layer are attached to the one surface of the insulating layer, when the conductive sheet is wound around the wire, in the vicinity of the adhesive, a gap is difficult to occur at the portion where the conductive sheets overlap each other.
In the above shield harness, preferably, the conductive layer is extended from an edge of the adhesive on the side of other end in the widthwise direction to the other end of the insulating layer.
Therefore, the gap is difficult to occur between the adhesive and the conductive layer in the widthwise direction. When the conductive sheet is wound around the plurality of electric wires, the gap is more difficult to occur.
In the above shield harness, preferably, the conductive layer has a thickness equal to that of the adhesive. Therefore, the gap is more difficult to occur in the vicinity of the adhesive.
In accordance with the third aspect of this invention, there is provided a shield harness comprising:
a plurality of first electric wires arranged in parallel;
a conductive thin film sheet having a conductive layer;
a second electric wire composed of a conductive core and a cladding which clads the core, wherein
the plurality of first electric wires are bunched,
the conductive layer at one end in the width direction of the conductive thin film sheet and the core of the second electric wire are bonded to each other, and
with the one end of the conductive thin film sheet located inside and the other end thereof located outside and both ends superposed on each other, the conductive thin film sheet is wound on an outer periphery of the outer periphery of the plurality of first electric wires.
In this configuration, since the conductive layer of the conductive thin film sheet and core of the second electric wire are bonded to each other, the second electric wire can be used as a drain wire. In this way, since the core of the second electric wire which can be employed as the drain wire and the conductive layer of the conductive thin film sheet are bonded to each other, the core of the second electric wire can be surely electrically connected to the conductive layer.
Further, since the core of the second electric wire and the conductive layer of the conductive thin film sheet are bonded to each other, in order to attach the core of the second electric wire to the conductive thin film sheet, any component which is separate from the conductive thin film sheet and second electric wire is not required. This contribute to prevent the number of components from being increased.
With the one end equipped with the second electric wire being located inside and the other end located outside, both ends are superposed on each other. Therefore, the portion where the core of the second electric wire and the conductive layer are bonded to each other is covered with the above other end, and not exposed.
In a preferred embodiment of the shield harness, the other end is superposed on an outside of the second electric wire. Therefore, the portion where the core of the second electric wire and the conductive layer is not exposed more surely.
In a preferred embodiment of the shield harness, the conductive thin film sheet includes an insulating layer stacked on the conductive layer, and with the conductive layer located inside and insulating layer located outside, the conductive thin film sheet is wound on the outer periphery of the outer periphery of the plurality of first electric wires.
In this configuration, since with the insulating layer located outside, since the conductive thin film sheet is wound on the outer periphery of the outer periphery of the plurality of first electric wires, the conductive layer is prevented from being exposed. Any component such as a protector or tube is not required in order to prevent the conductive layer from being exposed. This contributes to suppress the corrosion of the conductive layer. Since the insulating layer is located outside, it is possible to prevent the core of the second electric wire which is employed as the drain wire from being short-circuited to the other electric wire and electronic appliance outside the shield harness.
In accordance with the third aspect of this invention, there is also provided a method of manufacturing a shield harness comprising the steps of:
subjecting the insulating layer and the second electric wire superposed on each other to ultrasonic welding so that the conductive layer of the conductive thin film sheet and the core of the second electric wire are bonded to each other; and
with the conductive layer of the conductive thin film sheet located inside and the insulating layer located outside, winding the thin film conductive sheet on the outer periphery of the outer periphery of the plurality of first electric wires continuously from the one end of the thin film conductive sheet to the other end thereof.
In this method, since the core of the second electric wire and the conductive layer of the conductive thin film sheet are bonded to each other by the ultrasonic welding, in order to attach the core of the second electric wire to the conductive thin film sheet, any component which is separate from the conductive thin film sheet and second electric wire is not required. This contribute to prevent the number of components from being increased.
Further, since the conductive layer and core are bonded to each other by the ultrasonic welding, they can be surely metallic-bonded, and hence surely electrically connected to each other.
The conductive thin film sheet is wound on the outer periphery of the outer periphery of the plurality of first electric wires continuously from the one end of the thin film conductive sheet to the other end thereof. Therefore, the portion where the core of the second electric wire and the conductive layer are bonded to each other is covered with the above other end, and not exposed.
With the insulating layer located outside, since the conductive thin film sheet is wound on the outer periphery of the outer periphery of the plurality of first electric wires, the conductive layer is prevented from being exposed. Any component such as a protector or tube is not required in order to prevent the conductive layer from being exposed. This contributes to suppress the corrosion of the conductive layer.
Since the ultrasonic welding is performed with the second electric wire superposed on the insulating layer, the insulating layer and the cladding are removed from between the conductive layer and the core, it is not necessary to partially remove the insulating layer of the conductive thin film sheet and cladding of the second electric wire.
In accordance with the forth aspect of this invention, there is provided a shield harness comprising:
a plurality of first electric wires arranged in parallel;
a conductive thin film sheet having a conductive layer;
a second electric wire composed of a conductive core and a cladding which clads the core, wherein
the plurality of first electric wires are bunched,
the conductive thin film sheet is wound on an outer periphery of the outer periphery of the plurality of first electric wires, and
the conductive layer of the conductive thin film sheet and the core of the second electric wire are bonded to each other.
In this configuration, the conductive thin film sheet is wound on the outer periphery of the plurality of first electric wires and the conductive layer of the conductive thin film sheet and the core of the second electric wire are bonded to each other. Therefore, the second electric wire can be employed as a drain wire. Thus, the second electric wire can be branched from any position. Further, since the conductive layer of the conductive thin film sheet and the core of the second electric wire are bonded to each other, they can be surely electrically connected to each other.
In a preferred embodiment of the shield harness, the conductive thin film sheet includes an insulating layer stacked on the conductive layer, and with the conductive layer located inside and insulating layer located outside, the conductive thin film sheet is wound on the outer periphery of the outer periphery of the plurality of first electric wires.
In this configuration, with the insulating layer located outside, the conductive thin film sheet is wound on the outer periphery of the outer periphery of the plurality of first electric wires. Therefore, the conductive thin film sheet and hence the core of the second electric wire can be prevented from being short-circuited to the other electric wire or electric appliance outside the shield harness.
In accordance with the fourth aspect of this invention, there is provided a method of manufacturing the shield harness, comprising the steps of:
subjecting the insulating layer and the second electric wire superposed on each other to ultrasonic welding so that the conductive layer of the conductive thin film sheet and the core of the second electric wire are bonded to each other; and
with the conductive layer of the conductive thin film sheet located inside and the insulating layer located outside, winding the thin film conductive sheet on the outer periphery of the outer periphery of the plurality of first electric wires.
In this method, since the ultrasonic welding is performed with the second electric wire superposed on the insulating layer, the conductive layer at any position of the conductive thin film sheet and the core at any position of the second electric wire can be surely bonded to each other.
Since the ultrasonic welding is performed with the second electric wire superposed on the insulating layer, the insulating layer and the cladding are removed from between the conductive layer and the core owing to heat generated during the ultrasonic welding. For this reason, it is not necessary to partially remove the insulating layer of the conductive thin film sheet and cladding of the second electric wire.
Since the, conductive layer and the core are bonded to each other by the ultrasonic welding, in order to attach the core of the second electric wire to the conductive thin film sheet, it is not necessary to employ any component which is separate from the conductive thin film sheet and the second electric wire. This contribute to prevent the number of components from being increased.
Further, since the conductive layer and core are bonded to each other by the ultrasonic welding, they can be surely metallic-bonded, and hence surely electrically connected to each other.
In accordance with the fifth aspect of this invention, there isprovided a method for assembling a shield harness by winding a conductive thin film sheet having a conductive layer on an outer periphery of a plurality of electric wires arranged in parallel, comprising the steps of:
holding the conductive thin film sheet and the plurality of electric wires by the holding portion so that the plurality of electric wires are superposed on the one surface of the thin film conductive sheet at a central portion in a width direction of the conductive thin film sheet, and a conductive wire is superposed on the other surface of the conductive thin film sheet at one end thereof in the width direction;
superposing the one end as well as the conductive wire on the plurality of electric wires and attaching the one end to the other end in the width direction of the conductive thin film sheet; and
rolling the plurality of wires onto the other end so that the other end is attached on the other surface of the conductive thin film sheet.
In this method, the plurality of electric wires are superposed on the one surface of the thin film conductive sheet at a central portion in a width direction of the conductive thin film sheet, and a conductive wire is superposed on the other surface of the conductive thin film sheet at one end thereof in the width direction. After the one end as well as the conductive wire has been superposed on the plurality of first electric wires, the plurality of wires are rolled onto the other end. Therefore, the conductive wire is located between the one end of the conductive thin film sheet and the other end thereof. Thus, the conductive wire can be surely brought into contact with the conductive thin film sheet.
Therefore, by employing the second electric wire as the drain wire, the noise which tends to invade the core of each of the first electric wires can be dissipated surely through the conductive layer and the conductive wire.
In accordance with the fifth aspect of this invention, there is also provided a method for assembling a shield harness by winding a conductive thin film sheet having a conductive layer on an outer periphery of a plurality of electric wires arranged in parallel using a jig including a stand, a holding portion formed in a V-shape in section which is rotatably supported on the stand, and an urging means which urges the holding portion in a direction of leaving its opening from the stand and supports the holding portion in a state where the opening has left from the stand, comprising the steps: comprising the steps of:
holding the conductive thin film sheet and the plurality of electric wires so that the thin film conductive sheet is placed in the opening, the plurality of electric wires are superposed on the one surface of the thin film conductive sheet at a central portion in a width direction of the conductive thin film sheet, and a conductive wire is superposed on the other surface of the thin film conductive sheet at one end thereof in the width direction;
superposing the one end as well as the second wire on the plurality of electric wires and attaching the one end to the other end in the width direction of the conductive thin film sheet; and
bringing the holding portion toward the stand by the urging means against elastic restoring force of the urging means and rolling the plurality of electric wires onto the other end so that the other end is attached on the other surface of the conductive thin film sheet.
In this method, the jig is employed which includes a holding portion formed in a V-shape in section, and an urging means which urges the holding portion in a direction of leaving its opening from the stand and supports the holding portion in a state where the opening has left from the stand. Therefore, with the plurality of electric wires superposed on the conductive thin film sheet, the plurality of electric wires and thin film sheet can be surely held on the jig.
The holding portion is brought down on to the stand against the elastic restoring force of the urging means. Therefore, the plurality of electric wires can be surely rolled on the other end. Hence, with the conductive wire located between the one end of the conductive thin film sheet and the other end thereof, the shield harness can be assembled. The conductive wire can be surely brought into contact with the conductive thin film sheet. Therefore, by employing the conductive wire as the drain wire, the noise which tends to invade the core of each of the plurality of electric wires can be dissipated surely through the conductive layer and the second electric wire.
In a preferred embodiment of the assembling method, the conductive layer and the conductive wire are bonded to each other.
Because of such a configuration, the second electric wire and the conductive layer can be surely electrically connected to each other. Hence, by employing the second electric wire as the drain wire, the noise which tends to invade the core of each of the electric wires can be dissipated surely through the conductive layer and the conductive wire.
In a preferred embodiment of the assembling method, the conductive thin film sheet has an insulating layer stacked on the conductive layer,
the conductive wire is coated with a cladding, and
with the conductive layer located on the one surface of the conductive thin film sheet and the insulating layer located on the other surface thereof, the insulating layer and the cladding are welded to each other at a position where the conductive layer and the cladding are bonded.
In this method, with the plurality of electric wires located on the conductive layer of the conductive thin film sheet, the conductive thin film sheet is wound on the outer periphery of the plurality of electric wires. Therefore, with the insulating layer located outside, the conductive thin film sheet of the shield harness. Thus, the conductive wire which can be employed as the drain wire can be prevented from being short-circuited to the other electric wire or electronic appliance outside the shield harness.
Further, the insulating layer and cladding are welded to each other at the bonding portion where the conductive layer and core are bonded. Therefore, the mechanical strength of the bonding portion can be improved. The conductive layer and the core of the conductive wire can be surely electrically connected to each other. Therefore, by employing the conductive wire as the drain wire, the noise which tends to invade the core of each of the plurality of electric wires can be dissipated surely through the conductive layer and the conductive wire.
The above and other objects and features of the invention will be more apparent from the following description taken in conjunction with the accompanying drawings.